BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Roberto Pignatelli (University of Trento) DTSTART:20200421T130000Z DTEND:20200421T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/1 DESCRIPTION:Title: Rigid compact complex surfaces that are not infinitesimally rigid \nby Roberto Pignatelli (University of Trento) as part of Warwick alge braic geometry seminar\n\n\nAbstract\nA complex manifold is rigid if every small deformation of its complex structure is trivial. The usual argument for proving the rigidity of a complex manifold is by a well known "standa rd" cohomological criterium. Morrow and Kodaira posed in 1971 the problem of constructing a rigid manifold that does not satisfy it. \n\nI will pres ent a new criterium for rigidity of a manifold of dimension 2 that is more general than the standard one. As an application\, I will produce a famil y of examples satisfying our criterium and not the classical one\, so answ ering the above question. \n\nThis is a joint work with I. Bauer.\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Adam Gyenge (University of Oxford) DTSTART:20200428T130000Z DTEND:20200428T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/2 DESCRIPTION:Title: Hilbert and Quot schemes of simple surface singularities\nby Adam Gyenge (University of Oxford) as part of Warwick algebraic geometry s eminar\n\n\nAbstract\nThe Hilbert schemes of points on the affine complex plane has the structure of a Nakajima quiver variety. For a finite subgrou p G of SL(2\, C)\, I will discuss the construction of the Hilbert scheme o f n points on the Kleinian singularity C^2/G as a Nakajima quiver variety for the framed McKay quiver of G with a specific non-generic stability par ameter. I will also present a formula for the generating series collecting the Euler numbers of these varieties\, a specific case of which was prove d recently by Nakajima. Given enough time\, I will explain the analogous p roblem for certain Quot schemes of C^2/G. (Joint work with Alastair Craw\, Soren Gammelgaard and Balazs Szendroi).\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Jean-Louis Colliot-Thélène (CNRS et Université Paris-Saclay) DTSTART:20200609T130000Z DTEND:20200609T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/3 DESCRIPTION:Title: On the integral Tate conjecture for 1-cycles on the product of a curve and a surface over a finite field\nby Jean-Louis Colliot-Thélè ne (CNRS et Université Paris-Saclay) as part of Warwick algebraic geometr y seminar\n\n\nAbstract\nLet X be the product of a smooth projective curve C and a smooth projective surface S over a finite field F. Assume the Cho w group of zero-cycles on S is just Z over any algebraically closed field extension of F (example : Enriques surface). We give a simple condition on C and S which ensures that the integral Tate conjecture holds for 1-cycle s on X. An equivalent formulation is a vanishing result for unramified coh omology of degree 3. This generalizes a result of A. Pirutka (2016). It is a joint work with Federico Scavia (UBC\, Vancouver).\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Tyler Kelly (University of Birmingham) DTSTART:20200505T130000Z DTEND:20200505T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/4 DESCRIPTION:Title: A few aspects of hypergeometric functions in geometry and arithme tic\nby Tyler Kelly (University of Birmingham) as part of Warwick alge braic geometry seminar\n\n\nAbstract\nHypergeometric functions are special functions that go back all the way to Euler and come all the way to Mirro r Symmetry\, Hodge theory\, and Gromov-Witten Theory. I plan to give a (ve ry biased) stroll through some of their contexts/computations in algebraic geometry and Hodge theory\, and then explain the analogue of hypergeometr ic functions over finite fields. This will then give us a way to organise point counts on certain varieties over finite fields. This talk will invol ve joint work with C Doran\, A Salerno\, S Sperber\, U Whitcher\, and J Vo ight.\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Will Donovan (Yau MSC\, Tsinghua University) DTSTART:20200512T130000Z DTEND:20200512T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/5 DESCRIPTION:Title: Windows on the Pfaffian-Grassmannian correspondence\nby Will Donovan (Yau MSC\, Tsinghua University) as part of Warwick algebraic geome try seminar\n\n\nAbstract\nThe Pfaffian-Grassmannian correspondence has be en a key example in the development of Homological Projective Duality: it concerns certain pairs of non-birational Calabi-Yau threefolds which share a mirror partner\, and can be proved to be derived equivalent. Physically \, such an equivalence is associated to B-brane transport along a path in a mirror symmetry moduli space\, and is dependent on the homotopy class of that path: I give a mathematical implementation of this dependency\, in t erms of mutations of an exceptional collection on the relevant Grassmannia n. This follows a physical analysis of Hori and Eager-Hori-Knapp-Romo\, an d builds on work with Addington and Segal.\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Anthony Várilly-Alvarado (Rice University) DTSTART:20200519T130000Z DTEND:20200519T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/6 DESCRIPTION:Title: Quasi-hyperbolicity via explicit symmetric differentials\nby Anthony Várilly-Alvarado (Rice University) as part of Warwick algebraic g eometry seminar\n\n\nAbstract\nA surface X is algebraically quasi-hyperbol ic if it contains finitely many curves of genus 0 or 1. In 2006\, Bogomolo v and de Oliveira used asymptotic computations to show that sufficiently n odal surfaces of high degree in projective three-space carry symmetric dif ferentials\, and they used this to prove quasi-hyperbolicity of these surf aces. We explain how a granular analysis of their ideas\, combined with co mputational tools and insights\, yield explicit results for the existence of symmetric differentials\, and we show how these results can be used to give constraints on the locus of rational curves on surfaces like the Bart h Decic\, Buechi's surface\, and certain complete intersections of general type\, including the surface parametrizing perfect cuboids. This is joint work with Nils Bruin and Jordan Thomas.\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Ana-Maria Castravet (Versailles) DTSTART:20200616T130000Z DTEND:20200616T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/8 DESCRIPTION:Title: Exceptional collections on moduli spaces of pointed stable ration al curves\nby Ana-Maria Castravet (Versailles) as part of Warwick alge braic geometry seminar\n\n\nAbstract\nI will report on joint work with Jen ia Tevelev answering a question of Orlov. We prove that the Grothendieck-K nudsen moduli spaces of pointed stable rational curves with n markings adm it full\, exceptional collections that are invariant under the action of t he symmetric group $S_n$ permuting the markings. In particular\, a consequ ence is that the K-group with integer coefficients is a permutation $S_n$- lattice.\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Hans-Christian Graf von Bothmer (Hamburg) DTSTART:20200623T130000Z DTEND:20200623T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/9 DESCRIPTION:Title: Rigid\, not infinitesimally rigid surfaces with ample canonical b undle\nby Hans-Christian Graf von Bothmer (Hamburg) as part of Warwick algebraic geometry seminar\n\n\nAbstract\nIt was a long-standing problem of Morrow and Kodaira whether there are compact complex manifolds X with D ef(X) a non reduced point. The first examples answering this question in t he affirmative were given by Bauer and Pignatelli in 2018. As explained by Roberto Pignatelli in this seminar some weeks ago\, these are certain sur faces of general type that have nodal canonical models. These canonical mo dels are rigid AND infinitesimally rigid\, while their desingularizations are still rigid\, but not infinitesimally rigid anymore. One can therefore ask\, if this situation is typical for rigid\, not infinitesimally rigid surfaces of general type\, or if it is possible to have examples with smoo th canonical models. We answer this question also in the affirmative by co nstructing such a surface X via line arrangements and abelian covers. This construction was inspired by Vakil's version of „Murphy’s law in alge braic geometry“. (This is joint work with Christian Böhning and Roberto Pignatelli.)\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Enrica Mazzon (MPI Bonn) DTSTART:20200602T130000Z DTEND:20200602T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/10 DESCRIPTION:Title: Tropical affine manifolds from mirror symmetry to Berkovich geom etry\nby Enrica Mazzon (MPI Bonn) as part of Warwick algebraic geometr y seminar\n\n\nAbstract\nMirror symmetry is a fast-moving research area at the boundary between mathematics and theoretical physics. Originated from observations in string theory\, it suggests that certain geometrical obje cts (complex Calabi-Yau manifolds) should come in pairs\, in the sense tha t each of them has a mirror partner and the two share interesting geometri cal properties. In this talk\, I will introduce some notions relating mirr or symmetry to tropical geometry\, inspired by the work of Kontsevich-Soib elman and Gross-Siebert. In particular\, I will focus on the construction of a so-called “tropical affine manifold” using methods of non-archime dean geometry\, and the guiding example will be the case of K3 surfaces an d some hyper-Kähler varieties. This is based on joint work with Morgan Br own and a work in progress with Léonard Pille-Schneider.\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Michel van Garrel (Warwick) DTSTART:20200526T130000Z DTEND:20200526T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/11 DESCRIPTION:Title: Prelog Chow rings\nby Michel van Garrel (Warwick) as part of Warwick algebraic geometry seminar\n\n\nAbstract\nIn this joint work with Christian Böhning and Hans-Christian Graf von Bothmer\, we explore Chow rings in the setting of log geometry\, leading to the construction of prel og Chow rings of normal crossings varieties with smooth components. For a strictly semistable degeneration\, the prelog Chow ring of the central fib er admits a specialization morphism from the Chow group of the generic fib er. After introducing the definition\, I will describe examples illustrati on the construction.\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Victor Batyrev (Tübingen) DTSTART:20200630T130000Z DTEND:20200630T140000Z DTSTAMP:20260404T095735Z UID:WarwickAG/12 DESCRIPTION:Title: Fine interior of lattice polytopes: MMP and Mirror Symmetry\ nby Victor Batyrev (Tübingen) as part of Warwick algebraic geometry semin ar\n\n\nAbstract\nThe notion "Fine interior" of a lattice polytope P was i ntroduced by Miles Reid in his famous lectures on canonical singularities. A non-degenerated hypersurface in a d-dimensional algebraic torus T is bi rational to a Calabi-Yau if and only if the Fine interior of its Newton po lytope is a single lattice point. This is the starting point for my talk w ith the ambitious goal to explain my solutions to MMP and Mirror Symmetry for toric hypersurfaces.\n LOCATION:https://stable.researchseminars.org/talk/WarwickAG/12/ END:VEVENT END:VCALENDAR